When I started growing 15 yrs ago, it was with autos that I snuck into a winter flower-care room running 12/12. Since there was so little info about growing weed, didn't really know any difference. No where does any info state that autos REQUIRE more light, only that they CAN handle it.
Being an old nuclear inspector, I always had to qualify anything that makes change...comparing numbers shows that the increased costs of running more than 12/12 is just not equated by increased yeild. For 15 years now, I've grown every cannabis plant, auto and photo, on 12/12 and know for my own fact that I haven't lost anything.